Dead didymo cells found in Central Plateau river

Dead didymo cells have been found in some samples of water taken late last week from the Tongariro, Whakapapa, Mangatepopo and Whanganui Rivers.

Live cells need to be present before a waterway can be confirmed as infected with didymo.

The dead cells were in samples taken from two sites on the Tongariro River – Puketatara and downstream of the Rangipo Dam, and the one site each on the Whakapapa, Mangatepopo and Whanganui Rivers. The samples were taken as part of Genesis Energy’s monthly water quality sampling programme.

“As you would expect, we are treating this with urgency, and are working with our Central North Island partners to determine if there is any live didymo in the area,” said David Hayes, MAF Biosecurity New Zealand biosecurity response manager.

“All sites where dead didymo cells were found will be retested as well as several other sites nearby which have been identified as high value or high risk due to heavy use by river users. This work has already begun.

“We will also look at sample collection and laboratory processes to see if there has been any cross-contamination of samples.

“This is clearly a developing situation, and we will provide further information as soon as it is available.

Mr Hayes said a Central North Island didymo action group has been in place in the region for the last 18 months and has a response plan that will be implemented should live didymo be found in the area.

“Didymo has not been confirmed in the North Island yet, but every sample like this merely reinforces that the best defence is for all freshwater users to Check, Clean and Dry between waterways regardless of where they are in New Zealand.”

More information about didymo and cleaning methods is available on the MAF Biosecurity New Zealand website www.biosecurity.govt.nz.